Re: compiler generated output

Hello Gerd,

Gerd Isenberg <spamtrap@xxxxxxxxxx> schrieb:


> So the code snipped from AMD Optimization Guide is recommended
>
> Remainder of Signed Division by 2n or -(2n)
> ; In: EAX = dividend
> ; Out: EAX = remainder
> cdq ; Sign extend into EDX.
> and edx, (2^n - 1) ; Mask correction (abs(divisor) - 1)
> add eax, edx ; Apply pre-correction.
> and eax, (2^n - 1) ; Mask out remainder (abs(divisor) - 1)
> sub eax, edx ; Apply pre-correction if necessary.

Well, very interesting. I had to think about that code in order to
understand that it really works. ;)

Regards,
Spiro.

--
Spiro R. Trikaliotis http://cbm4win.sf.net/
http://www.trikaliotis.net/ http://www.viceteam.org/

.

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